Micro hybrid generator system drone

ABSTRACT

An unmanned aerial vehicle comprising at least one rotor motor. The rotor motor is powered by a micro hybrid generation system. The micro hybrid generator system comprises a rechargeable battery configured to provide power to the at least one rotor motor, a small engine configured to generate mechanical power, a generator motor coupled to the small engine and configured to generate AC power using the mechanical power generated by the small engine, a bridge rectifier configured to convert the AC power generated by the generator motor to DC power and provide the DC power to either or both the rechargeable battery and the at least one rotor motor, and an electronic control unit configured to control a throttle of the small engine based, at least in part, on a power demand of at least one load, the at least one load including the at least one rotor motor.

This application claims priority to U.S. Provisional Application No.62/079,866, filed on Nov. 14, 2014, U.S. Provisional Application No.62/079,890, filed on Nov. 14, 2014, U.S. Provisional Application No.62/080,482, filed on Nov. 17, 2014, and U.S. Provisional Application No.62/080,554, filed on Nov. 17, 2014, each of which is incorporated byreference in its entirety.

FIELD OF THE INVENTION

This invention relates to a micro hybrid generator system drone.

BACKGROUND OF THE INVENTION

A typical conventional multi-rotor UAV is significantly less complex,easier to operate, less expensive, and easier to maintain than a typicalconventional single rotor aerial vehicle, such as a helicopter orsimilar type aerial vehicle. For example, a conventional multi-rotor UAVmay include four or more rotor motors, four or more propellers coupledthereto, four or more electronic speed controllers, a flight controlsystem (auto pilot), an RC radio control, a frame, and a rechargeablebattery, such as a lithium polymer (LiPo) or similar type rechargeablebattery. In contrast, a single rotor aerial vehicle, such as ahelicopter, may have thousands of parts. Additionally, single rotoraerial vehicles are also notoriously difficult to operate, diagnoseproblems, and are expensive to maintain.

Multi-rotor UAVs can perform vertical take-off and landing (VTOL) andare capable of aerial controls with similar maneuverability to singlerotor aerial vehicles. Multi-rotor UAVs are relatively easy to assembleand may use commercial off the shelf (COTS) hardware including autopilot flight controllers that are easily adaptable to standardconfigurations, e.g., a quad-rotor, a hex-rotor, an octo-rotor, and thelike.

A typical conventional multi-rotor UAV relies solely on rechargeablebattery or batteries to provide power to drive the rotor motors coupledto the propellers to provide flight. A typical conventional multi-rotorUAV includes a lithium polymer (LiPo) battery which may provide about150 to 210 Wh/kg. This may provide a typical loaded flight time of about15 minutes and an unloaded flight time of about 32 to 45 minutes.Advance lithium sulfur batteries may also be used which provide about400 Wh/kg of power. In this case, the flight times are about 30 minutesin a loaded configuration.

In operation, the battery is used for the entire flight of theconventional multi-rotor UAV. Thus, when the battery is depleted, theUAV will stop operating. If the UAV is in flight, this can result in acatastrophic crashing of the UAV. Additionally, if aggressive maneuversare needed during flight, such as quickly veering away from an object ormoving quickly to avoid a potential threat, such maneuvers requireinstantaneous peak power which can quickly deplete the battery andsignificantly reduce flight time significantly.

Thus, conventional battery powered multi-rotor UAVs have limitedendurance and payload and provide no backup power in the event thebattery supply is depleted. Additionally, conventional commercial UAVsare very expensive and not commercially viable at scale today.

Conventional portable generators are heavy and may be difficult totransport to desired locations. Additionally, micro grid power systemsused for electric grid power backup or ultra-micro power systems used incell towers for power backup rely solely on batteries to provide theneeded backup power.

Thus, there is a need for a small, lightweight, portable generatorsystem which can provide power in such applications. Additionally, thereis a need for UAVs with improved operational characteristics. Forexample, there is a need for UAVs capable of operating for longerdurations.

SUMMARY

The following implementations and aspects thereof are described andillustrated in conjunction with systems, tools, and methods that aremeant to be exemplary and illustrative, not necessarily limiting inscope. In various implementations one or more of the above-describedproblems have been addressed, while other implementations are directedto other improvements.

In various embodiments, an unmanned aerial vehicle comprising at leastone rotor motor configured to drive at least one propeller to rotate,rotation of the at least one propeller generating thrust and causing theunmanned aerial vehicle to fly. In various embodiments, the unmannedaerial vehicle comprises an electronic speed control configured tocontrol an amount of power provided to the at least one rotor motor.Further, in various embodiments, an unmanned aerial vehicle comprises amicro hybrid generator system configured to provide power to the atleast one rotor motor comprising. In various embodiments, an unmannedaerial vehicle comprises a rechargeable battery configured to providepower to the at least one rotor motor. Further, in various embodiments,an unmanned aerial vehicle comprises a small engine configured togenerate mechanical power. Additionally, in various embodiments, anunmanned aerial vehicle comprises a generator motor coupled to the smallengine and configured to generate AC power using the mechanical powergenerated by the small engine. Further, in various embodiments, anunmanned aerial vehicle comprises a bridge rectifier configured toconvert the AC power generated by the generator motor to DC power andprovide the DC power to either or both the rechargeable battery and theat least one rotor motor. In various embodiments, an unmanned aerialvehicle comprises an electronic control unit configured to control athrottle of the small engine based, at least in part, on a power demandof at least one load, the at least one load including the at least onerotor motor.

These and other advantages will become apparent to those skilled in therelevant art upon a reading of the following descriptions and a study ofthe several examples of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a diagram of an example micro hybrid generator system.

FIG. 2 depicts a side perspective view of a micro hybrid generatorsystem.

FIG. 3A depicts a side view of a micro hybrid generator.

FIG. 3B depicts an exploded side view of a micro hybrid generator.

FIG. 4 is a perspective view of a micro hybrid generator system.

FIG. 5 is a perspective view of a UAV integrated with a micro hybridgenerator system.

FIG. 6 depicts a graph comparing energy density of different UAV powersources.

FIG. 7 depicts a graph of market potential for UAVs against flight timefor an example two plus hours of flight time micro hybrid generatorsystem of one or more embodiments when coupled to a UAV is able toachieve and an example of the total market potential vs. endurance forthe micro hybrid generator system for UAVs of this invention.

FIG. 8 shows an example flight pattern of a UAV with a micro hybridgenerator system.

FIG. 9 depicts a system diagram for a micro hybrid generator system withdetachable subsystems.

FIG. 10a depicts a diagram of a micro hybrid generator system withdetachable subsystems integrated as part of a UAV.

FIG. 10b depicts a diagram of a micro hybrid generator system withdetachable subsystems integrated as part of a ground robot.

FIG. 11 shows a ground robot with a detachable flying pack in operation.

FIG. 12 shows a control system of a micro hybrid generator system.

FIG. 13 shows a top perspective view of a top portion of a drone poweredthrough a micro hybrid generator system.

FIG. 14 shows a top perspective view of a bottom portion of a dronepowered through a micro hybrid generator system.

FIG. 15 shows a top view of a bottom portion of a drone powered througha micro hybrid generator system.

FIG. 16 shows a side perspective view of a micro hybrid generatorsystem.

FIG. 17 shows a side perspective view of a micro hybrid generatorsystem.

DETAILED DESCRIPTION OF THE INVENTION

Aside from the preferred embodiment or embodiments disclosed below, thisinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Thus, it is to be understood that theinvention is not limited in its application to the details ofconstruction and the arrangements of components set forth in thefollowing description or illustrated in the drawings. If only oneembodiment is described herein, any claims based on this provisionalpatent application are not to be limited to that embodiment. Moreover,any such claims are not to be read restrictively unless there is clearand convincing evidence manifesting a certain exclusion, restriction, ordisclaimer.

One or more embodiments of a micro hybrid generator system provide asmall portable micro hybrid generator power source with energyconversion efficiency. In UAV applications, the micro hybrid generatorsystem of one or more embodiments can be used to overcome the weight ofthe vehicle, the micro hybrid generator drive, and fuel necessary toprovide extended endurance and payload capabilities in UAV applications.In other applications, the micro hybrid generator device system can beused as a small, lightweight, portable generator for residential andcommercial applications or as a micro-grid generator or anultra-micro-grid generator, and the like.

The micro hybrid generator system of one or more embodiment of cancomprise two separate power systems. A first power system included aspart of the micro hybrid generator system can be a small and efficientgasoline powered engine coupled to a generator motor. In variousembodiments, the first power system serves as a primary source of powerof the micro hybrid generator system. A second power system, included aspart of the micro hybrid generator system, can be a high energy densityrechargeable battery. Together, the first power system and the secondpower system, combine to form a high energy continuous power source andhigh peak power availability for a UAV, including when a UAV performsaggressive maneuvers. Further, one of the first power system and thesecond power system can serve as back-up power sources of the microhybrid generator system if a corresponding one of the first power systemor the second power system fails. In various embodiments, the microhybrid generator system can serve as a portable, lightweight generatorto provide power in residential and commercial applications or as amicro-grid or ultra-micro-grid generator.

FIG. 1 depicts a diagram of an example micro hybrid generator system 10.The micro hybrid generator system 10 includes a fuel source 12, e.g., avessel for storing gasoline, a mixture of gasoline and oil mixture, orsimilar type fuel or mixture. The fuel source 12 provides fuel to asmall engine 14, of a first power system. The small engine 14 can usethe fuel provided by the fuel source 12 to generate mechanical energy.In one example, the small engine 14 can have dimensions of about 12″ by11″ by 6″ and a weight of about 3.5 lbs. to allow for integration in aUAV. In one example, the small engine 14 may be an HWC/Zenoah G29 RCE 3DExtreme available from Zenoah, 1-9 Minamidai Kawagoe, Saitama 350-1165,Japan. The micro hybrid generator system 10 also includes a generatormotor 16 coupled to the small engine 14. The generator motor 16functions to generate AC output power using mechanical power generatedby the small engine 14. In various embodiments, a shaft of the smallengine 14 includes a fan that dissipates heat away from the small engine14. In various embodiments, the generator motor 16 is coupled to thesmall engine 14 through a polyurethane coupling.

In one embodiment, the micro hybrid generator system 10 can provide 1.8kW of power. Further in the embodiment, the micro hybrid generatorsystem 10 can include a small engine 14 that provides approximately 3horsepower and weighs approximately 1.5 kg, e.g. a Zenoah® G29RC Extremeengine. In the embodiment, the micro hybrid generator system 10 includesa generator motor 16 that is a brushless motor, 380 Kv, 8 mm shaft, partnumber 5035-380, available from Scorpion Precision Industry®. In anotherembodiment, the micro hybrid generator system 10 can provide 10 kW ofpower. Further in the another embodiment, the micro hybrid generatorsystem 10 can include a small engine 14 that provides approximatelybetween 15-16.5 horsepower and weighs approximately 7 pounds, e.g. aDesert Aircraft® DA-150. In the another embodiment, the micro hybridgenerator system 10 includes a generator motor 16 that is a Joby Motors®JM1 motor.

The micro hybrid generator system 10 includes a bridge rectifier 18 anda rechargeable battery 20. The bridge rectifier 18 is coupled betweenthe generator motor 16 and the rechargeable battery 20 and converts theAC output of the generator motor 16 to DC power to charge therechargeable battery 20 or provide DC power to load 78 by line 82 orpower to DC-to-AC inverter 84 by line 86 to provide AC power to load 90.The rechargeable battery 20 may provide DC power to load 92 by line 94or to DC-to-AC inverter 96 by line 98 to provide AC power to load 100.In one example, an output of the bridge rectifier 18 and/or therechargeable battery 20 of micro hybrid generator system 10 is providedby line 102 to one or more electronic speed control devices (ESC) 24integrated in one or more rotor motors 25 as part of an UAV. The ESC 24can control the DC power provided by bridge rectifier 18 and/orrechargeable battery 20 to one or more rotor motors provided bygenerator motor 16. In one example, the ESC 24 can be a T-Motor® ESC 45A(2-6S) with SimonK. In one example, the bridge rectifier 18 can be amodel #MSD100-08, diode bridge 800V 100A SM3, available from MicrosemiPower Products Group®.

In various embodiments, the ESC 24 can control an amount of powerprovided to one or more rotor motors 25 in response to input receivedfrom an operator. For example, if an operator provides input to move aUAV to the right, then the ESC 24 can provide less power to rotor motors25 on the right of the UAV to cause the rotor motors to spin propellerson the right side of the UAV slower than propellers on the left side ofthe UAV. As power is provided at varying levels to one or more rotormotors 25, a load, e.g. an amount of power provided to the one or morerotor motors 25, can change in response to input received from anoperator.

In one embodiment, the rechargeable battery 20 may be a LiPo battery,providing 3000 mAh, 22.2V 65C, Model PLU65-30006, available from PulseUltra Lipo®, China. In other designs, the rechargeable battery 20 may bea lithium sulfur (LiSu) rechargeable battery or similar type ofrechargeable battery.

The micro hybrid generator system 10 includes an electronic control unit(ECU) 22. The ECU 22, and other applicable systems described in thispaper, can be implemented as a computer system, a plurality of computersystems, or parts of a computer system or a plurality of computersystems. In general, a computer system will include a processor, memory,non-volatile storage, and an interface. A typical computer system willusually include at least a processor, memory, and a device (e.g., a bus)coupling the memory to the processor. The processor can be, for example,a general-purpose central processing unit (CPU), such as amicroprocessor, or a special-purpose processor, such as amicrocontroller.

The memory can include, by way of example but not limitation, randomaccess memory (RAM), such as dynamic RAM (DRAM) and static RAM (SRAM).The memory can be local, remote, or distributed. The bus can also couplethe processor to non-volatile storage. The non-volatile storage is oftena magnetic floppy or hard disk, a magnetic-optical disk, an opticaldisk, a read-only memory (ROM), such as a CD-ROM, EPROM, or EEPROM, amagnetic or optical card, or another form of storage for large amountsof data. Some of this data is often written, by a direct memory accessprocess, into memory during execution of software on the computersystem. The non-volatile storage can be local, remote, or distributed.The non-volatile storage is optional because systems can be created withall applicable data available in memory.

Software is typically stored in the non-volatile storage. Indeed, forlarge programs, it may not even be possible to store the entire programin the memory. Nevertheless, it should be understood that for softwareto run, if necessary, it is moved to a computer-readable locationappropriate for processing, and for illustrative purposes, that locationis referred to as the memory in this paper. Even when software is movedto the memory for execution, the processor will typically make use ofhardware registers to store values associated with the software, andlocal cache that, ideally, serves to speed up execution. As used herein,a software program is assumed to be stored at an applicable known orconvenient location (from non-volatile storage to hardware registers)when the software program is referred to as “implemented in acomputer-readable storage medium.” A processor is considered to be“configured to execute a program” when at least one value associatedwith the program is stored in a register readable by the processor.

In one example of operation, a computer system can be controlled byoperating system software, which is a software program that includes afile management system, such as a disk operating system. One example ofoperating system software with associated file management systemsoftware is the family of operating systems known as Windows® fromMicrosoft Corporation of Redmond, Wash., and their associated filemanagement systems. Another example of operating system software withits associated file management system software is the Linux operatingsystem and its associated file management system. The file managementsystem is typically stored in the non-volatile storage and causes theprocessor to execute the various acts required by the operating systemto input and output data and to store data in the memory, includingstoring files on the non-volatile storage.

The bus can also couple the processor to the interface. The interfacecan include one or more input and/or output (I/O) devices. The I/Odevices can include, by way of example but not limitation, a keyboard, amouse or other pointing device, disk drives, printers, a scanner, andother I/O devices, including a display device. The display device caninclude, by way of example but not limitation, a cathode ray tube (CRT),liquid crystal display (LCD), or some other applicable known orconvenient display device. The interface can include one or more of amodem or network interface. It will be appreciated that a modem ornetwork interface can be considered to be part of the computer system.The interface can include an analog modem, isdn modem, cable modem,token ring interface, Ethernet interface, satellite transmissioninterface (e.g. “direct PC”), or other interfaces for coupling acomputer system to other computer systems. Interfaces enable computersystems and other devices to be coupled together in a network.

A computer system can be implemented as a module, as part of a module,or through multiple modules. As used in this paper, a module includesone or more processors or a portion thereof. A portion of one or moreprocessors can include some portion of hardware less than all of thehardware comprising any given one or more processors, such as a subsetof registers, the portion of the processor dedicated to one or morethreads of a multi-threaded processor, a time slice during which theprocessor is wholly or partially dedicated to carrying out part of themodule's functionality, or the like. As such, a first module and asecond module can have one or more dedicated processors, or a firstmodule and a second module can share one or more processors with oneanother or other modules. Depending upon implementation-specific orother considerations, a module can be centralized or its functionalitydistributed. A module can include hardware, firmware, or softwareembodied in a computer-readable medium for execution by the processor.The processor transforms data into new data using implemented datastructures and methods, such as is described with reference to the FIGS.in this paper.

The ECU 22 is coupled to the bridge rectifier 18 and the rechargeablebattery 20. The ECU 22 can be configured to measure the AC voltage ofthe output of the generator motor 16, which is directly proportional tothe revolutions per minute (RPM) of the small engine 14, and compares itto the DC power output of the bridge rectifier 18. The ECU 22 cancontrol the throttle of the small engine 14 to cause the DC power outputof the bridge rectifier 18 to increase or decrease as the load changes,e.g., a load of one or more electric motors 25 or one or more of loads78, 90, 92, and 100. In one example, the ECU 22 can be an Arduino® MEGA2560 Board R3. In various embodiments, a load of one or more electricmotors 25 can change as the ESC 24 changes an amount of power providedto the electric motors 25. For example, if a user inputs to increase thepower provided to the electric motors 25 subsequently causing the ESC 24to provide more power to the electric motors 25, then the ECU 22 canincrease the throttle of the small engine 14 to cause the production ofmore power to provide to the electronic motors 25.

The ECU 22 can function to maintain voltage output of loads by readingthe sensed analog voltage, converting these to ADC counts, comparing thecount to that corresponding to a desired voltage, and increasing ordecreasing the throttle of the small engine 14 according to theprogrammed gain if the result is outside of the dead band.

In one example, the micro hybrid generator system 10 can provide about1,800 watts of continuous power, 10,000 watts of instantaneous power(e.g., 6S with 16,000 mAh pulse battery) and has a 1,500 Wh/kg gasolineconversion rate. In one example, the micro hybrid generator system 10has dimensions of about 12″ by 12″ by 12″ and a weight of about 8 lbs.

FIG. 2 depicts a side perspective view of a micro hybrid generatorsystem 10. FIG. 3A depicts a side view of a micro hybrid generator 10.FIG. 3B depicts an exploded side view of a micro hybrid generator 10.The micro hybrid generator system 10 includes a small engine 14 coupledto generator motor 16. In one embodiment, the small engine 14 includes acoupling/cooling device 26 which provides coupling of the shaft of thegenerator motor 16 to the shaft of small engine 14 and also providescooling with sink fins 27. For example, FIGS. 3A and 3B, show in furtherdetail one embodiment of coupling/cooling device 26, which includescoupling/fan 28 with set screws 30 that couple shaft 32 of generatormotor 16 and shaft 34 of small engine 14. Coupling/cooling device 26 mayalso include rubber coupling ring 36.

In various embodiments, the micro hybrid generator system 10 includescomponents to facilitate transfer of heat away from the micro hybridgenerator system 10 and/or is integrated within a UAV to increaseairflow over components that produce heat. For example, the hybridgenerator system 10 can include cooling fins on specific components,e.g. the rectifier, to transfer heat away from the micro hybridgenerator system. In various implementations, the micro hybrid generatorsystem 10 includes components and is integrated within a UAV to causeheat to be transferred towards the exterior of the UAV.

In various embodiments, the micro hybrid generator system 10 and/or aUAV integrating the micro hybrid generator system 10 is configured toallow 406 cubic feet per minute of airflow across at least one componentof the micro hybrid generator system 10. A small engine 14 of the microhybrid generator system 10 can be run at an operating temperature 150°C. and if an ambient temperature in which the micro hybrid generatorsystem 10, in order to remove heat generated by the small engine 14, anairflow of 406 cubic feet per minute is achieved across at least thesmall engine 16. Further in various embodiments, the small engine 14 isoperated at 16.5 Horsepower and generates 49.2 kW of waste heat, e.g.each head of the small engine produces 24.6 kW of waste heat. In variousembodiments, electric ducted fans are used to concentrate airflow overthe engine heads. For example, 406 cubic feet per minute airflow can beachieved over engine heads of the small engine 14 using electric ductedfans.

In various embodiments, the micro hybrid generator system 10 isintegrated as part of a UAV using a dual vibration damping system. Asmall engine 14 of the micro hybrid generator system can utilizecouplings to accommodate for misalignment between the engine andgenerator. A dual vibration damping system using both compression andtorsional dampers can provide damping between the micro hybrid generatorsystem 10 and a structure to which it is mounted, e.g. a drone. In oneexample, the small engine 14 produces a mean torque of 1.68 Nm at 10,000RPM.

In various embodiments, a urethane coupling is used to couple the smallengine 14 to the generator motor 16. Further in the one example, theurethane coupling can have a durometer value of between 90A to 75D.Example urethane couplings used to secure, at least part of, the microhybrid generator system 10 to a UAV include L42 Urethane, L100 Urethane,L167 Urethane, and L315 Urethane. Urethane couplings used to secure, atleast part of, the micro hybrid generator system 10 to a UAV can have atensile strength between 20 MPa and 62.0 MPa, between 270 to 800%elongation at breaking, a modulus between 2.8 MPa and 32 MPa, anabrasion index between 110% and 435%, and a tear strength split between12.2 kN/m and 192.2 kN/m.

Small engine 14, FIGS. 2 and 3, also includes fly wheel 38 which reducesmechanical noise and/or engine vibration. Preferably, small engine 14includes Hall Effect sensor 40, FIG. 3, and Hall Effect magnet coupledto fly wheel 38 as shown. In one example, Hall-effect sensor 40 may beavailable from RCexl Min Tachometer®, Zhejiang Province, China.

When small engine 14 is operational, fly wheel 38 spins at a speed basedon throttle. The spinning speed of fly wheel 38 is measured by Halleffect sensor 40. The voltage generated by Hall effect sensor 40 isinput into an ECU 22. In various embodiments, the ECU 22 compares theoutput by the generator motor 16 to ensure that a proper voltage ismaintained and the battery does not discharge beyond a certainthreshold. ECU 22 can then control the throttle of either or both thegenerator motor 16 and the small engine 14 to increase or decrease thevoltage as needed to supply power to one or more of loads 78, 90, 92,and/or 100 or one or more rotor motors 25.

Small engine 14 may also include a starter motor 42, servo 44, muffler46, and vibrational mount 48.

FIG. 4 is a perspective view of a micro hybrid generator system 10. Themicro hybrid generator system 10 includes a small motor 14 and generatormotor 16 coupled to a bridge rectifier 18.

FIG. 5 is a perspective view of a UAV 150 integrated with a micro hybridgenerator system 10. The UAV 150 includes six rotor motors 25 eachcoupled to propellers 60, however it is appreciated that a UAVintegrated with a micro hybrid generator system 10 can include more orless rotor motors and propeller. The UAV 150 can include a Px4 flightController® implemented as part of a 3 DR Pixhawk®.

In one embodiment, small engine 14, as shown in FIGS. 1-5 may be startedusing an electric starter 50. Fuel source 12, as shown in FIG. 1 (alsoshown in FIG. 5) delivers fuel to small engine 14 to spin its rotorshaft directly coupled to generator motor 16 as shown in FIG. 3 andapplies a force to generator motor 16. The spinning of generator motor16 generates electricity and the power generated by motor generator 16is proportional to the power applied by shaft of small engine 14.Preferably, a target rotational speed of generator motor 16 isdetermined based on the KV (rpm/V) of generator motor 16. For example,if a target voltage of 25 Volt DC is desired, the rating of generatormotor 16 would be about 400 KV. The rotational speed of the small engine14 may be determined by the following equations:RPM=KV (RPM/Volt)×Target Voltage (VDC)  (1)RPM=400 KV×25 VDC  (2)RPM=10,000  (3)

In this example, for generator motor 16 to generate 25 VDC output, theshaft of generator motor 16 coupled to the shaft of small engine 14needs to spin at about 10,000 RPM.

As the load, e.g., one or more motors 25 or one or more of loads 78, 90,92, and/or 100, is applied to the output of generator motor 16, thevoltage output of the battery drops, which is sensed by the ECU 22,which subsequently can increase a throttle of the small engine 14. Inthis case, ECU 22 can be used to help regulate the throttle of smallengine 14 to maintain a consistent output voltage that varies withloads, preventing the system from losing power under load. ECU 22 canact like a standard governor for gasoline engines but instead ofregulating an RPM, it can regulate a target voltage output of either orboth a bridge rectifier and a generator motor 16 based on a closed loopfeedback controller.

Power output from generator motor 16 can be in the form of alternatingcurrent (AC) which needs to be rectified by bridge rectifier 18. Bridgerectifier 18 can convert the AC power into direct current (DC) power, asdiscussed above. In various embodiments, the output power of the microhybrid generator system 10 can be placed in a “serial hybrid”configuration, where the generator power output by generator motor 16may be available to charge the rechargeable battery 20 or provide powerto another external load.

In operation, there can be at least two available power sources when themicro hybrid generator system 10 is functioning. A primary source can befrom the generator motor 16 through directly from the bridge rectifierand a secondary power source can be from the rechargeable battery 20.Therefore, a combination of continuous power availability and high peakpower availability is provided, which may be especially well-suited forUAV applications or a portable generator applications. In cases whereeither primary (generator motor 16) power source is not available,system 10 can still continue to operate for a short period of time usingpower from rechargeable battery 20 allowing a UAV to sustain safetystrategy, such as an emergency landing.

When micro hybrid generator system 10 is used for UAVs, the followingconditions can be met to operate the UAV effectively and efficiently: 1)the total continuous power (watts) can be greater than power required tosustain UAV flight, 2) the power required to sustain a UAV flight is afunction of the total weight of the vehicle, the total weight of thehybrid engine, the total weight of fuel, and the total weight of thepayload), where:Total Weight (gram)=vehicle dry weight+small engine 14 weight+fuelweight+payload  (4)and, 3) based on the vehicle configuration and aerodynamics, aparticular lift motor will have an efficiency rating (grams/watt) of 11,where:Total Power Required to Fly=η×Weight (gram)  (5)

In cases where the power required to sustain flight is greater than theavailable continuous power, the available power or total energy ispreferably based on the size and configuration of the rechargeablebattery 20. A configuration of the rechargeable battery 20 can be basedon a cell configuration of the rechargeable battery 20, a cell rating ofthe rechargeable battery 20, and/or total mAh of the rechargeablebattery 20. In one example, for a 6S, 16000 mAh, 25C battery pack, thetotal energy is determined by the following equations:Total Energy=Voltage×mAh=25VDC (6S)×16000 mAh=400 Watt*Hours   (6)Peak Power Availability=Voltage=mAh=C Rating=25 VDC×16000 mAh×25C=10,400 Watts  (7)Total Peak Time=400 Watt*Hours/10,400 Watts=138.4 secs  (8)Further in the one example, the rechargeable battery 20 will be able toprovide 10,400 Watts of power for 138.4 seconds in the event of primarypower failure from small engine 14. Additionally, the rechargeablebattery 20 may be able to provide up to 10,400 Watts of available powerfor flight or payload needs instantaneous peak power for short periodsof time needed for aggressive maneuvers.

The result is micro hybrid generator system 10 when coupled to a UAVefficiently and effectively provides power to fly and maneuver the UAVfor extended periods of time with higher payloads than conventionalmulti-rotor UAVs. In one example, the micro hybrid generator system 10can provide a loaded (3 lb. load) flight time of up to about 2 hours 5mins, and an unloaded flight time of about 2 hours and 35 mins Moreover,in the event that the fuel source runs out or the small engine 14 and/orhe generator motor 16 malfunctions, the micro hybrid generator system 10can use the rechargeable battery 20 to provide enough power to allow theUAV to perform a safe landing. In various embodiments, the rechargeablebattery 20 can provide instantaneous peak power to a UAV for aggressivemaneuvers, for avoiding objects, or threats, and the like.

In various embodiments, the micro hybrid generator system 10 can providea reliable, efficient, lightweight, portable generator system which canbe used in both commercial and residential applications to provide powerat remote locations away from a power grid and for a micro-gridgenerator, or an ultra-micro-grid generator.

In various embodiments, the micro hybrid generator system 10 can be usedfor an applicable application, e.g. robotics, portable generators,micro-grids and ultra-micro-grids, and the like, where an efficient highenergy density power source is required and where a fuel source isreadily available to convert hydrocarbon fuels into useable electricpower. The micro hybrid generator system 10 has been shown to besignificantly more energy efficient than various forms of rechargeablebatteries (Lithium Ion, Lithium Polymer, Lithium Sulfur) and even FuelCell technologies typically used in conventional UAVs.

FIG. 6 depicts a graph comparing energy density of different UAV powersources. In various embodiments, the micro hybrid generator system 10can use conventional gasoline which is readily available at low cost andprovide about 1,500 Wh/kg of power for UAV applications, e.g., asindicated at 58 in FIG. 6. Conventional UAVs which rely entirely onbatteries can provide a maximum energy density of about 1,000 Wh/kg whenusing an energy high density fuel cell technology, indicated at 60 about400 Wh/kg when using lithium sulfur batteries, indicated at 62, and onlyabout 200 Wh/kg when using a LiPo battery, indicated at 64.

FIG. 7 depicts a graph of market potential for UAVs against flight timefor an example two plus hours of flight time micro hybrid generatorsystem 10 of one or more when coupled to a UAV is able to achieve and anexample of the total market potential vs. endurance for the micro hybridgenerator system 10 for UAVs of this invention.

In various embodiments, the micro hybrid generator power systems 10 canbe integrated as part of a UAV or similar type aerial robotic vehicle toperform as a portable flying generator using the primary source of powerto sustain flight of the UAV and then act as a primary power source ofpower when the UAV has reached its destination and is not in flight. Forexample, when a UAV which incorporates micro hybrid system 10, e.g., UAV150, FIG. 5, is not in flight, the available power generated by microhybrid system can be transferred to one or more of external loads 78,90, 92, and/or 100 such that micro hybrid generator system 10 operatesas a portable generator. Micro hybrid system generator 10 can providecontinuous peak power generation capability to provide power at remoteand often difficult to reach locations. In the “non-flight portablegenerator mode”, micro hybrid system 10 can divert the available powergeneration capability towards external one or more of loads 78, 90, 92,and/or 100. Depending on the power requirements, one or more of DC-to-ACinverters 84, 96 may be used to convert DC voltage to standard AC power(120 VAC or 240 VAC).

In operation, micro hybrid generator system 10 coupled to a UAV, such asUAV 150, FIG. 5, will be able to traverse from location to locationusing aerial flight, land, and switch on the power generator to convertfuel into power.

FIG. 8 shows an example flight pattern of a UAV with a micro hybridgenerator system 10. In the example flight pattern shown in FIG. 8, theUAV 150, with micro hybrid system 10 coupled thereto, begins at locationA loaded with fuel ready to fly. The UAV 150 then travels from locationA to location B and lands at location B. The UAV 150 then uses microhybrid system 10 to generate power for local use at location B, therebyacting as a portable flying generator. When power is no longer needed,the UAV 150 returns back to location A and awaits instructions for thenext task.

In various embodiments, the UAV 150 uses the power provided by microhybrid generator system 10 to travel from an initial location to aremote location, fly, land, and then generate power at the remotelocation. Upon completion of the task, the UAV 150 is ready to acceptcommands for its new task. All of this can be performed manually orthrough an autonomous/automated process. In various embodiments, the UAV150 with micro hybrid generator system 10 can be used in an applicableapplication where carrying fuel and a local power generator are needed.Thus, the UAV 150 with a micro hybrid generator system 10 eliminates theneed to carry both fuel and a generator to a remote location. The UAV150 with a micro hybrid generator system 10 is capable of powering boththe vehicle when in flight, and when not in flight can provide the sameamount of available power to external loads. This may be useful insituations where power is needed for the armed forces in the field, inhumanitarian or disaster relief situations where transportation of agenerator and fuel is challenging, or in situations where there is arequest for power that is no longer available.

FIG. 9 depicts a diagram of another system for a micro hybrid generatorsystem 10 with detachable subsystems. FIG. 10a depicts a diagram of amicro hybrid generator system 10 with detachable subsystems integratedas part of a UAV. FIG. 10b depicts a diagram of a micro hybrid generatorsystem 10 with detachable subsystems integrated as part of a groundrobot. In various embodiments, a tether line 201 is coupled to the DCoutput of bride rectifier 18 and rechargeable battery 20 of a microhybrid control system 10. The tether line 201 can provide DC poweroutput to a tether controller 202. The tether controller 202 is coupledbetween a tether cable 206 and a ground or aerial robot 208. Inoperation, as discussed in further detail below, the micro hybridgenerator system 10 provides tethered power to the ground or aerialrobot 208 with the similar output capabilities as discussed above withone or more of the FIGS. in this paper.

The system shown in FIG. 9 can include additional detachable components250 integrated as part of the system, e.g., data storage equipment 252,communications equipment 254, external load sensors 256, additionalhardware 258, and various miscellaneous equipment 260 that can becoupled via data tether 262 to tether controller 202.

In one example of operation of the system shown in FIG. 9, the systemmay be configured as part of a flying robot or UAV, such as flying robotor UAV 270, FIG. 10, or as ground robot 272. Portable tethered roboticsystem 200 starts a mission at location A. All or an applicablecombination of the subsystems and ground, the tether controller,ground/aerial robot 208 can be powered by the micro hybrid generatorsystem 10. The Portable tethered robotic system 200 travels either byground, e.g., using ground robot 272 powered by micro hybrid generatorsystem 10 or by air using flying robot or UAV 270 powered by microhybrid generator system 10 to desired remote location B. At location B,portable tethered robotic system 200 configured as flying robot 270 orground robot 272 can autonomously decouple micro hybrid generator system10 and/or detachable subsystem 250, indicated at 274, which remaindetached while ground robot 272 or flying robot or UAV 270 areoperational. When flying robot or UAV 270 is needed at location B,indicated at 280, flying robot or UAV 270 can be operated using powerprovided by micro hybrid generator system coupled to tether cable 206.When flying robot or UAV 270 no longer has micro hybrid generator system10 and/or additional components 250 attached thereto, it issignificantly lighter and can be in flight for a longer period of time.In one example, flying robot or UAV 270 can take off and remain in ahovering position remotely for extended periods of time using the powerprovided by micro hybrid generator system 10.

Similarly, when ground robot 272 is needed at location B, indicated at290, it may be powered by micro hybrid generator system 10 coupled totether line 206 and will also be significantly lighter without microhybrid generator system 10 and/or additional components 250 attachedthereto. Ground robot 272 can also be used for extended periods of timeusing the power provide by micro hybrid generator system 10.

FIG. 11 shows a ground robot 300 with a detachable flying pack inoperation. The detachable flying pack 302 includes micro hybridgenerator system 10. The detachable flying pack is coupled to the groundrobot 300 of one or more embodiments. The micro hybrid generator system10 is embedded within the ground robot 300. The ground robot 300 isdetachable from the flying pack 302. With such a design, a majority ofthe capability is embedded deep within the ground robot 300 which canoperate 100% independently of the flying pack 302. When the ground robot300 is attached to the flying pack 302, the flying pack 302 is poweredfrom micro hybrid generator system 10 embedded in the ground robot 300and the flying pack 302 provides flight. The ground robot 300 platformcan be a leg wheel or threaded base motion.

In one embodiment, the ground robot 300 may include the detachableflying pack 302 and the micro hybrid generator system 10 coupled theretoas shown in FIG. 11. In this example, the ground robot 300 is awheel-based robot as shown by wheels 304. In this example, the microhybrid generator system 10, includes fuel source 12, small engine 14,generator motor 16, bridge rectifier 18, rechargeable battery 20, ECU22, and optional inverters 84 and 96, as discussed above with referenceto one or more FIGS. in this paper. The micro hybrid generator system 10also preferably includes data storage equipment 252, communicationsequipment 254, external load sensors 256, additional hardware 258, andmiscellaneous communications 260 coupled to data line 262 as shown. Theflying pack 302 is preferably, an aerial robotic platform such as afixed wing, single rotor or multi rotor, aerial device, or similar typeaerial device.

In one embodiment, the ground robot 300 and the aerial flying pack 302are configured as a single unit. Power is delivered the from microhybrid generator system 10 and is used to provide power to flying pack302, so that ground robot 300 and flying pack 302 can fly from locationA to location B. At location B, ground robot 304 detaches from flyingpack 302, indicated at 310, and is able to maneuver and operateindependently from flying pack 302. Micro hybrid generator system 10 isembedded in ground robot 300 such that ground robot 304 is able to beindependently powered from flying pack 302. Upon completion of theground mission, ground robot 300 is able to reattached itself to flyingpack 302 and return to location A. All of the above operations can bemanual, semi-autonomous, or fully autonomous.

In one embodiment, flying pack 302 can traverse to a remote location anddeliver ground robot 300. At the desired location, there is no need forflying pack 302 so it can be left behind so that ground robot 300 cancomplete its mission without having to carry flying pack 302 as itspayload. This may be useful for traversing difficult and challengingterrains, remote locations, and in situations where it is challenging totransport ground robot 300 to the location. Exemplary applications mayinclude remote mine destinations, remote surveillance andreconnaissance, and package delivery services where flying pack 302cannot land near an intended destination. In these examples, adesignated safe drop zone for flying pack can be used and local deliveryis completed by ground robot 300 to the destination.

In various embodiments, then a mission is complete, ground robot 272 orflying robot or UAV 270 can be autonomously coupled back to micro hybridgenerator system 10. Additional detachable components 250 can auto beautonomously coupled back micro hybrid generator system 10. Portabletethered robotic system 200 with a micro hybrid generator system 10configured a flying robot or UAV 270 or ground robot 272 then returns tolocation A using the power provided by micro hybrid generator system 10.

The result is portable tethered robotic system 200 with a micro hybridgenerator system 10 is able to efficiently transport ground robot 272 orflying robot or UAV 270 to remote locations, automatically decoupleground robot 272 or flying robot or UAV 270, and effectively operate theflying robot 270 or ground robot 272 using tether power where it may bebeneficial to maximize the operation time of the ground robot 270 orflying robot or UAV 272. System 200 provides modular detachabletethering which may be effective in reducing the weight of the tetheredground or aerial robot thereby reducing its power requirementssignificantly. This allows the aerial robot or UAV or ground robot tooperate for significantly longer periods of time when compared to theoriginal capability where the vehicle components are attached and thevehicle needs to sustain motion. System 200 eliminates the need toassemble a generator, robot and tether at remote locations and thereforesaves time, resources, and expense. Useful applications of system 200may include, inter alia, remote sensing, offensive or defensive militaryapplications and/or communications networking, or multi-vehiclecooperative environments, and the like.

FIG. 12 shows a control system of a micro hybrid generator system. Themicro hybrid generator system includes a power plant 400 coupled to anignition module 402. The ignition module 402 functions to start thepower plant 400 by providing a physical spark to the power plant 402.The ignition module 402 is coupled to an ignition battery eliminatorcircuit (IBEC) 404. The IBEC 404 functions to power the ignition module402.

The power plant 400 is configured to provide power. The power plant 400includes a small engine and a generator. The power plant is controlledby the ECU 406. The ECU 406 is coupled to the power plant through athrottle servo. The ECU 406 can operate the throttle servo to control athrottle of a small engine to cause the power plant 400 to eitherincrease or decrease an amount of produced power. The ECU 406 is coupledto a voltage divider 408. Through the voltage divider 408, the ECU candetermine an amount of power the load/vehicle 414 is drawing todetermine whether to increase, decrease, or keep a throttle of a smallengine constant.

The power plant is coupled to a power distribution board 410. The powerdistribution board 410 can distribute power generated by the power plant400 to either or both a battery pack 412 and a load/vehicle 414. Thepower distribution board 410 is coupled to a battery eliminator circuit(BEC) 416. The BEC 416 provides power to the ECU 406 and a receiver 418.The receiver 418 controls the IBEC 404 and functions to cause the IBEC404 to power the ignition module 402. The receiver 418 also sendsinformation to the ECU 406 used in controlling a throttle of a smallengine of the power plant 400. The receiver 418 to the ECU informationrelated to a throttle position of a throttle of a small engine and amode in which the micro hybrid generation system is operating.

FIG. 13 shows a top perspective view of a top portion 500 of a dronepowered through a micro hybrid generator system. The top portion 500 ofthe drone shown in FIG. 13 includes six rotors 502-1 . . . 502-6(hereinafter “rotors 502”). The rotors 502 are caused to spin bycorresponding motors 504-1 . . . 504-6 (hereinafter “motors 504”). Themotors 504 can be powered through a micro hybrid generator system. Thetop portion 500 of a drone includes a top surface 506. Edges of the topsurface 506 can be curved to reduce air drag and improve aerodynamicperformance of the drone. The top surface includes an opening 508through which air can flow to aid in dissipating heat away from at leasta portion of a micro hybrid generator system. In various embodiments, atleast a portion of an air filter is exposed through the opening 508.

FIG. 14 shows a top perspective view of a bottom portion 550 of a dronepowered through a micro hybrid generator system 10. The micro hybridgenerator system 10 includes a small engine 14 and a generator motor 16to provide power to motors 504. The rotor motors 504 and correspondingrotors 502 are positioned away from a main body of a bottom portion 550of the drone through arms 552-1 . . . 552-6 (hereinafter “arms 552”). Anouter surface of the bottom portion of the bottom portion 550 of thedrone and/or the arms 552 can have edges that are curved to reduce airdrag and improve aerodynamic performance of the drone.

FIG. 15 shows a top view of a bottom portion 550 of a drone poweredthrough a micro hybrid generator system 10. The rotor motors 504 andcorresponding rotors 502 are positioned away from a main body of abottom portion 550 of the drone through arms 552 An outer surface of thebottom portion of the bottom portion 550 of the drone and/or the arms552 can have edges that are curved to reduce air drag and improveaerodynamic performance of the drone.

FIG. 16 shows a side perspective view of a micro hybrid generator system10. The micro hybrid generator system 10 shown in FIG. 16 is capable ofproviding 1.8 kW of power. The micro hybrid generator system 10 includea small engine 14 coupled to a generator motor 16. The small engine 14can provide approximately 3 horsepower. The generator motor 16 functionsto generate AC output power using mechanical power generated by thesmall engine 14.

FIG. 17 shows a side perspective view of a micro hybrid generator system10. The micro hybrid generator system 10 shown in FIG. 17 is capable ofproviding 10 kW of power. The micro hybrid generator system 10 include asmall engine 14 coupled to a generator motor. The small engine 14 canprovide approximately 15-16.5 horsepower. The generator motor functionsto generate AC output power using mechanical power generated by thesmall engine 14.

Although specific features of the invention are shown in some drawingsand not in others, this is for convenience only as each feature may becombined with any or all of the other features in accordance with theinvention. The words “including”, “comprising”, “having”, and “with” asused herein are to be interpreted broadly and comprehensively and arenot limited to any physical interconnection. Moreover, any embodimentsdisclosed in the subject application are not to be taken as the onlypossible embodiments. Other embodiments will occur to those skilled inthe art.

We claim:
 1. An unmanned aerial vehicle comprising: at least one rotormotor configured to drive at least one propeller to rotate around anaxis of rotation, rotation of the at least one propeller generatingthrust and causing the unmanned aerial vehicle to fly; an electronicspeed control configured to control an amount of power provided to theat least one rotor motor; and a micro hybrid generator system configuredto provide power to the at least one rotor motor comprising: arechargeable battery configured to provide power to the at least onerotor motor; a small engine configured to generate mechanical power; agenerator motor coupled to the small engine and configured to generateAC power using the mechanical power generated by the small engine, thegenerator motor having a shaft oriented parallel to the axis of rotationof the at least one propeller and oriented vertically with respect tothe ground when the unmanned aerial vehicle is airborne; a couplingdevice coupling a rotor of the small engine to the generator motor, thecoupling device including a fan oriented to provide air flow to thesmall engine; a bridge rectifier configured to convert the AC powergenerated by the generator motor to DC power and provide the DC power toeither or both the rechargeable battery and the at least one rotormotor; and an electronic control unit configured to control a throttleof the small engine based, at least in part, on a power demand of atleast one load, the at least one load including the at least one rotormotor.
 2. The unmanned aerial vehicle of claim 1, wherein the couplingdevice comprises a polyurethane coupling.
 3. The unmanned aerial vehicleof claim 1, further comprising a throttle servo coupled to the throttleof the small engine and operated by the electronic control unit tocontrol the throttle of the small engine to control power output of thegenerator motor according to the power demand of the at least one load.4. The unmanned aerial vehicle of claim 1, further comprising a powerdistribution board configured to distribute DC power from either or boththe rechargeable battery or the bridge rectifier to the at least oneload.
 5. The unmanned aerial vehicle of claim 1, wherein the smallengine includes a fly wheel, the fly wheel configured with a sensor thatgenerates a voltage based on a spinning speed of the fly wheel.
 6. Theunmanned aerial vehicle of claim 5, wherein the electronic control unitis configured to control the throttle of the small engine based on thevoltage generated by the sensor.
 7. The unmanned aerial vehicle of claim1, wherein the rechargeable battery is configured to provide the powerto the at least one rotor motor when the small engine and the generatormotor are turned off.
 8. The unmanned aerial vehicle of claim 1, whereinthe micro hybrid generator system is joined to the unmanned aerialvehicle through a plurality of rubber dampers.
 9. The unmanned aerialvehicle of claim 1, wherein the micro hybrid generator system isconfigured to generate at least 10 kW of power.
 10. The unmanned aerialvehicle of claim 1, wherein the micro hybrid generator system isconfigured to generate at least 1.8 kW of power.
 11. The unmanned aerialvehicle of claim 1, wherein the small engine produces 3 horsepower ofmechanical power and weighs 1.5 kg.
 12. The unmanned aerial vehicle ofclaim 1, wherein the small engine produces between 15 and 16.5horsepower of mechanical power and weighs less than 7.5 pounds.
 13. Theunmanned aerial vehicle of claim 1, wherein the micro hybrid generatorsystem includes cooling fins to dissipate heat away from the microhybrid generator system to an exterior of the unmanned aerial vehicle.14. The unmanned aerial vehicle of claim 1, wherein the micro hybridgenerator system is configured to create 406 cubic feet per minute ofairflow across at least a portion of the small engine during at least aportion of a flight of the unmanned aerial vehicle.
 15. The unmannedaerial vehicle of claim 1, further comprising electric ducted fansconfigured to dissipate heat away from the small engine.
 16. Theunmanned aerial vehicle of claim 1, wherein the micro hybrid generatorsystem is integrated as part of the unmanned aerial vehicle using a dualvibration damping system.
 17. The unmanned aerial vehicle of claim 1,wherein the micro hybrid generator system is configured to provide powerto an external load of the unmanned aerial vehicle.
 18. The unmannedaerial vehicle of claim 1, wherein the micro hybrid generator system isconfigured to provide power to the external load remote from a powergrid.
 19. The unmanned aerial vehicle of claim 2, wherein thepolyurethane coupling has a tensile strength between 20 MPa and 62 MPa.